
.pptbox{
    width: 400px;
    height: 100px;
    position: relative;
    overflow: hidden;
}

.pptbox  .innerwrapper{
    width:2400px;/*当增加了li之后，大盒子的宽度也要相应的增加 这里增加了两个li，每个400，所以ul 从原来的1600变成了2400*/
    height: 100px;
    list-style: none;
    position: absolute;
    left: -400px;
}

.innerwrapper li
{
    width:400px;
    height:100px;
    float: left;
}
.innerwrapper li a
{
    display: block;
}

.innerwrapper li a img
{
    width: 400px;
    height:100px;
    display:block;
}

.btnleft{
    width: 20px;
    height: 50px;
    position: absolute;
    left:0;
    top:25px;
    background-color: black;
    background-image:url(../imgs/arrow-left.png);
    background-position: center center;
    background-repeat:no-repeat;
    cursor: pointer;
    z-index: 1;
    color:#fff;
}

.btnright{
    width: 20px;
    height: 50px;
    position: absolute;
    right:0;
    top:25px;
    background-color: black;
    background-image:url(../imgs/arrow-right.png);
    background-position: center center;
    background-repeat:no-repeat;
    cursor: pointer;
    z-index: 1;
    color:#fff;
    
}

/*控制按钮开始*/

.controls{
    width:96px;
    position: absolute;
    left:152px;
    bottom:10px;
    list-style: none;
}
.controls li{
    width: 20px;
    height:20px;
    background-color: gold;
    float: left;
    margin-right:2px;
    text-align: center;
    border-radius:10px ;
    cursor: pointer;
}

.controls li.current
{
    background-color:aqua;
    color: brown;
}

/*控制按钮结束*/